For example, Patent Literature 1 discloses a lens drive device of an optical equipment. This device is provided with a rotational shaft having an externally threaded portion and a cylindrical portion formed on the outer circumference thereof, a supporting portion which supports each end of the rotational shaft, a gear fixed to the rotational shaft, a motor which is connected to a drive gear meshing the foregoing gear and rotationally drives the rotational shaft, a lens holder having a tubular portion whose inner circumference surface is disposed with an internally threaded portion engaging with the externally threaded portion of the rotational shaft and a fitting portion which slidably contacts the cylindrical portion of the rotational shaft, a guide shaft provided in parallel with the rotational shaft which supports the lens holder together with the rotational shaft, and a spring urging the rotational shaft to the supporting portion. The lens holder is supported by the rotational shaft via the tubular portion. Furthermore, the tubular portion is the portion of the lens holder that is driven during movement of the lens holder.
The lens drive device rotationally drives the motor and rotates the rotational shaft via the drive gear and via the gear, so as to move the lens holder along the optical axis direction of the lens while guiding the lens holder along the guide shaft via the tubular portion by engagement between an externally threaded portion of the rotational shaft and an internally threaded portion of the tubular portion of the lens holder.    Patent Literature 1: Unexamined Japanese Patent Application KOKAI Publication No. H09-32902 (FIG. 7)